I do this fairly often, and I print off the lettering that I want, in about 50 point. I then use a drawing enlarger and enlarge it to the size I want. Alternatively, you could print off the lettering full scale and use carbon paper to transfer it.

I also believe that you can do enlargements at an office supply store fairly cheap(here it is $0.08/page). It might be cheaper than the ink that you use printing one character to a page.